System, apparatus and method for supplying electric power, apparatus and method for receiving electric power

ABSTRACT

An electric power supply system includes an electric power reception apparatus and an electric power supply apparatus adapted to supply electric power to the electric power reception apparatus when the electric power reception apparatus is placed on the electric power supply apparatus. The electric power supply apparatus includes a plurality of electric power supply units adapted to supply electric power by electromagnetic induction to the electric power reception apparatus. A selection unit of the electric power supply apparatus selects, from the total plurality of electric power supply units, a plurality of electric power supply units whose location corresponds to a position where the electric power reception apparatus is placed, and a control unit controls the supply of electric power such that electric power is supplied to the electric power reception apparatus from the selected plurality of electric power supply units.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/887,017 filed May 3, 2013, which is a continuation of U.S.patent application Ser. No. 13/546,400 filed Jul. 11, 2012 (now U.S.Pat. No. 8,446,251), which is a continuation of U.S. patent applicationSer. No. 12/683,289 filed Jan. 6, 2010 (now U.S. Pat. No. 8,222,991),which is a continuation application of U.S. patent application Ser. No.11/592,960 filed Nov. 6, 2006 (now U.S. Pat. No. 7,733,215), which is acontinuation application of U.S. patent application Ser. No. 11/365,933,filed Mar. 2, 2006 (now abandoned), and which claims the benefit ofpriority from Japanese Patent Application JP 2005-059747, filed in theJapanese Patent Office on Mar. 3, 2005, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system, apparatus and method forsupplying electric power, an apparatus and a method for receivingelectric power, a storage medium and a program, and more particularly toa system, apparatus and method for supplying electric power, anapparatus and a method for receiving electric power, a storage mediumand a program, that allow it to supply electric power to an electricpower reception apparatus in an easy and efficient manner.

2. Description of the Related Art

In many electronic devices such as a PDA (Personal Digital Assistance)device or a digital portable telephone, a battery is charged such bysupplying electric power to the battery from an AC adapter connected viaa plug to an AC power source. That is, electric power is supplied to abattery of an electronic device from a power source via a power supplycable.

It has been proposed to wirelessly supply electric power to anelectronic device from an electric power supply apparatus without usinga power supply cable. For example, Japanese Unexamined PatentApplication Publication No. 6-133476 discloses a technique of supplyingelectric power by electromagnetically inducing a current in anelectromagnetic induction coil of a power receiver system from anelectromagnetic induction coil of a master system.

In a technique disclosed in Japanese Unexamined Patent ApplicationPublication No. 2003-224937, an electric power supply apparatus has aplurality of electric power supply coils. The electric power supplyapparatus sequentially selects one of electric power supply coils andpasses a current through the selected coil. In an electric powerreception apparatus placed on a placement surface of the electric powersupply apparatus, one electric power reception coil and oneidentification tag coil receive an electromagnetic wave generated by theelectric power supply coil, and electromotive force is induced in theelectric power reception coil and the identification tag coil. Inresponse, an ID is transmitted from the identification tag coil to theelectric power supply apparatus. If the electric power supply apparatusreceives the ID, the electric power supply apparatus stores the IDtogether with the index of the electric power supply coil that are beingused. In the following operation, passing of the current through theelectric power supply coil is controlled in accordance with the storedinformation.

SUMMARY OF THE INVENTION

In the known electric power supply system, electric power is suppliedfrom a particular one of power supply coils of the electric power supplyapparatus to the electric power reception coil of the electric powerreception apparatus, and thus it takes a long time to completely chargethe battery.

In view of the above, it is desirable to provide a technique ofsupplying electric power to an electric power reception apparatus toquickly charge a battery.

According to an embodiment of the present invention, there is providedan electric power supply system including an electric power supplyapparatus and an electric power reception apparatus, wherein theelectric power supply apparatus includes a plurality of electric powersupply means for supplying electric power by electromagnetic inductionto the electric power reception apparatus, a selection means forselecting, from a total plurality of electric power supply means, aplurality of electric power supply means whose location corresponds to aposition where the electric power reception apparatus is placed, areceiving means for receiving control information for controlling thesupply of the electric power, the control information being wirelesslytransmitted from the electric power reception apparatus, and a controlmeans for controlling the supply of the electric power according to thecontrol information such that the electric power is supplied to theelectric power reception apparatus from the selected plurality ofelectric power supply means, and wherein the electric power receptionapparatus includes an electric power reception means for receiving theelectric power supplied by the electromagnetic induction from theselected plurality of electric power supply means, and a transmittingunit for wirelessly transmitting the control information when the supplyof electric power by the electromagnetic induction from the selectedplurality of electric power supply means is received.

According to an embodiment of the present invention, there is providedan electric power supply apparatus including a plurality of electricpower supply means for supplying electric power by electromagneticinduction to the electric power reception apparatus, a selection meansfor selecting, from a total plurality of electric power supply means, aplurality of electric power supply means whose location corresponds to aposition where the electric power reception apparatus is placed, acommunication means for receiving control information for controllingthe supply of the electric power, the control information beingwirelessly transmitted from the electric power reception apparatus, anda control means for controlling the supply of the electric poweraccording to the control information such that the electric power issupplied to the electric power reception apparatus from the selectedplurality of electric power supply means.

The control means may transmit and receive information to or from theelectric power reception apparatus via the communication means toauthenticate the electric power reception apparatus.

The selection means may select electric power supply means such that ifthe communication means receives, from the electric power receptionapparatus, information notifying that the electric power receptionapparatus has received electric power in response to a magnetic fieldsequentially generated by the plurality of electric power supply means,the selection means selects the electric power supply means, which wasgenerating the magnetic field at the point of time at which thecommunication means received the information, as the electric powersupply means at the location corresponding to the location where theelectric power reception apparatus is placed.

The electric power supply apparatus may further include a detectionmeans for detecting an overcurrent that flows through an electric powersupply means when the electric power supply means generates the magneticfield, and the selection means may make a selection such that if anovercurrent is detected by the detection means before the communicationmeans receives information indicating that electric power has beensupplied, the selection means does not select the electric power supplymeans through which the detected overcurrent is flowing.

According to an embodiment of the present invention, there is providedan electric power supply method including the steps of selecting, from atotal plurality of electric power supply units, a plurality of electricpower supply units whose location corresponds to a position where theelectric power reception apparatus is placed, receiving controlinformation for controlling the supply of electric power, the controlinformation being wirelessly transmitted from the electric powerreception apparatus, and controlling the supply of the electric poweraccording to the control information such that the electric power issupplied to the electric power reception apparatus from the selectedplurality of electric power supply units.

According to an embodiment of the present invention, there is provided astorage medium in which a program is stored, the program including thesteps of selecting, from a total plurality of electric power supplyunits, a plurality of electric power supply units whose locationcorresponds to a position where the electric power reception apparatusis placed, receiving control information for controlling the supply ofelectric power, the control information being wirelessly transmittedfrom the electric power reception apparatus, and controlling the supplyof the electric power according to the control information such that theelectric power is supplied to the electric power reception apparatusfrom the selected plurality of electric power supply units.

According to an embodiment of the present invention, there is provided aprogram for use by a computer to execute a process including the stepsof selecting, from a total plurality of electric power supply units, aplurality of electric power supply units whose location corresponds to aposition where the electric power reception apparatus is placed,receiving control information for controlling the supply of electricpower, the control information being wirelessly transmitted from theelectric power reception apparatus, and controlling the supply of theelectric power according to the control information such that theelectric power is supplied to the electric power reception apparatusfrom the selected plurality of electric power supply units.

According to an embodiment of the present invention, there is providedan electric power reception apparatus including at least one electricpower reception means for receiving electric power supplied byelectromagnetic induction from a plurality of electric power supplyunits, and a transmitting unit for wirelessly transmitting controlinformation for controlling the supply of the electric power to anelectric power supply apparatus when the electric power is supplied byelectromagnetic induction from the electric power supply units.

According to an embodiment of the present invention, there is providedan electric power reception method including the steps of receivingelectric power supplied by electromagnetic induction from a plurality ofelectric power supply units, and wirelessly transmitting controlinformation for controlling the supply of the electric power to anelectric power supply apparatus when the electric power is supplied byelectromagnetic induction from the electric power supply units.

In the electric power supply system described above, the electric powersupply apparatus supplies electric power such that a plurality ofelectric power supply means supply electric power by electromagneticinduction to the electric power reception apparatus, the selection meansselects, from the total plurality of electric power supply means, aplurality of electric power supply means whose location corresponds tothe position where the electric power reception apparatus is placed, thecommunication means receives control information for controlling thesupply of the electric power, the control information being wirelesslytransmitted from the electric power reception apparatus, and the controlmeans controls the supply of the electric power according to the controlinformation such that the electric power is supplied to the electricpower reception apparatus from the selected plurality of electric powersupply means, and the electric power reception apparatus receiveselectric power such that the electric power reception means receives theelectric power supplied by the electromagnetic induction from theselected plurality of electric power supply means, and the transmittingunit wirelessly transmits the control information when the supply ofelectric power by the electromagnetic induction from the selectedplurality of electric power supply means is received.

In the electric power supply apparatus, the electric power supplymethod, the storage medium on which the program is stored, and theprogram, described above, a plurality of electric power supply unitswhose location corresponds to a position where the electric powerreception apparatus is placed are selected from the total plurality ofelectric power supply units, control information is received which isinformation for controlling the supply of the electric power and whichis wirelessly transmitted from the electric power reception apparatus,and the supply of the electric power is controlled according to thecontrol information such that the electric power is supplied to theelectric power reception apparatus from the selected plurality ofelectric power supply units.

In the electric power reception apparatus and the electric powerreception method described above, electric power is supplied byelectromagnetic induction from a plurality of electric power supplyunits, and control information for controlling the supply of theelectric power is transmitted to the electric power supply apparatuswhen the electric power is supplied by electromagnetic induction fromthe electric power supply units.

The present invention provides the advantage that electric is power issupplied to an electric power reception apparatus in a quick manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an example of a construction of apower supply system according to an embodiment of the present invention;

FIG. 2 is a diagram viewed from above and showing the electric powersupply apparatus shown in FIG. 1 in a state in which an electric powerreception apparatus is placed on a placement surface of the electricpower supply apparatus, wherein for the purpose of illustration, lowerparts hidden below upper parts are also shown.

FIG. 3 is a block diagram showing an example of a construction of theelectric power supply apparatus shown in FIG. 1;

FIG. 4 is a block diagram showing an example of a construction of theelectric power reception apparatus shown in FIG. 1;

FIG. 5 is a flow chart illustrating a process of selecting an electricpower supply unit;

FIG. 6 is a diagram showing a placement surface on which there is aforeign substance;

FIG. 7 is a diagram showing an electric power supply apparatus in astate in which a plurality of electric power reception apparatus and/orforeign substances are present on the electric power supply apparatus;

FIG. 8 is a flow chart illustrating a process of authenticating anelectric power reception apparatus;

FIG. 9 is a flow chart illustrating a process of supplying electricpower to an electric power reception apparatus;

FIG. 10 is a flow cart of a process performed by an electric powerreception apparatus to receive electric power; and

FIG. 11 is diagram showing another example of a construction of anelectric power reception unit of an electric power reception apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before embodiments of the present invention are described,correspondence between specific examples of parts/steps in theembodiments and those in the respective claims is described. Thisdescription is intended to assure those embodiments supporting theclaimed invention are described in this specification. Thus, even if anelement in the following embodiments is not described as relating to acertain feature of the present invention, that does not necessarily meanthat the element does not relate to that feature of the claims.Conversely, even if an element is described herein as relating to acertain feature of the claims, that does not necessarily mean that theelement does not relate to other features of the claims.

Furthermore, this description should not be construed as restrictingthat all the aspects of the invention disclosed in the embodiments aredescribed in the claims. That is, the description does not deny theexistence of aspects of the present invention that are described in theembodiments but not claimed in the invention of this application, i.e.,the existence of aspects of the present invention that in future may beclaimed by a divisional application, or that may be additionally claimedthrough amendments.

According to an embodiment of the present invention there is provided anelectric power supply system including at least one electric powerreception apparatus and an electric power supply apparatus adapted tosupply electric power to the at least electric power receptionapparatus, wherein the electric power supply apparatus (for example, anelectric power supply apparatus 1 shown in FIG. 1) includes a pluralityof electric power supply means (for example, electric power supply units11 shown in FIG. 3) for supplying electric power by electromagneticinduction to the electric power reception apparatus, a selection means(for example, a selector 72 shown in FIG. 3) for selecting, from thetotal plurality of electric power supply means, a plurality of electricpower supply means whose location corresponds to a position where theelectric power reception apparatus is placed, a receiving means (forexample, a communication unit 73 shown in FIG. 3) for receiving controlinformation for controlling the supply of the electric power, thecontrol information being wirelessly transmitted from the electric powerreception apparatus, and a control means (for example, an electric powersupply controller 71 shown in FIG. 3) for controlling the supply of theelectric power according to the control information such that theelectric power is supplied to the electric power reception apparatusfrom the selected plurality of electric power supply means, and whereinthe electric power reception apparatus (for example, an electric powerreception apparatus 2 shown in FIG. 1) includes an electric powerreception means (for example, an electric power reception unit 21 shownin FIG. 4) for receiving the electric power supplied by theelectromagnetic induction from the selected plurality of electric powersupply means, and a transmitting unit (for example, a communication unit107 shown in FIG. 4) for wirelessly transmitting the control informationwhen the supply of electric power by the electromagnetic induction fromthe selected plurality of electric power supply means is received.

According to an embodiment of the invention, there is provided anelectric power supply apparatus (for example, an electric power supplyapparatus 1 shown in FIG. 1) adapted to supply electric power to atleast one electric power reception apparatus, the electric power supplyapparatus including a plurality of electric power supply means (forexample, electric power supply units 11 shown in FIG. 3) for supplyingelectric power by electromagnetic induction to the electric powerreception apparatus, a selection means (for example, a selector 72 shownin FIG. 3) for selecting, from the total plurality of electric powersupply means, a plurality of electric power supply means whose locationcorresponds to a position where the electric power reception apparatusis placed, a communication means (for example, a communication unit 73shown in FIG. 3) for receiving control information for controlling thesupply of the electric power, the control information being wirelesslytransmitted from the electric power reception apparatus, and a controlmeans (for example, an electric power supply controller 71 shown in FIG.3) for controlling the supply of the electric power according to thecontrol information such that the electric power is supplied to theelectric power reception apparatus from the selected plurality ofelectric power supply means.

The electric power supply apparatus may further include a detectionmeans (for example, a current detector 53 shown in FIG. 3) for detectingan overcurrent that flows through an electric power supply means whenthe electric power supply means generates a magnetic field, and theselection means may make a selection such that if an overcurrent isdetected by the detection means before the communication means receivesinformation indicating that electric power has been supplied, theselection means does not select the electric power supply means throughwhich the detected overcurrent is flowing.

According to an embodiment of the present invention, there is providedan electric power supply method for an electric power supply apparatus(for example, an electric power supply apparatus 1 shown in FIG. 1)including a plurality of electric power supply units (for example,electric power supply units 11 shown in FIG. 2) for supplying electricpower by electromagnetic induction to at least one electric powerreception apparatus (for example, an electric power reception apparatus2 shown in FIG. 1) placed on the electric power supply apparatus, themethod including the steps of selecting, from a total plurality ofelectric power supply units, a plurality of electric power supply unitswhose location corresponds to a position where the electric powerreception apparatus is placed (for example, in step S51 shown in FIG.5), receiving control information for controlling the supply of theelectric power, the control information being wirelessly transmittedfrom the electric power reception apparatus (for example, in step S89shown in FIG. 8), and controlling the supply of the electric poweraccording to the control information such that the electric power issupplied to the electric power reception apparatus from the selectedplurality of electric power supply units (for example, in step S111shown in FIG. 9).

According to an embodiment of the present invention, there is provided astorage medium in which a computer-readable program is stored, for useto execute an electric power supply process by an electric power supplyapparatus (for example, an electric power supply apparatus 1 shown inFIG. 1) including a plurality of electric power supply units (forexample, electric power supply units 11 shown in FIG. 2) for supplyingelectric power by electromagnetic induction to at least one electricpower reception apparatus (for example, an electric power receptionapparatus 2 shown in FIG. 1) placed on the electric power supplyapparatus, the method including the steps of selecting, from a totalplurality of electric power supply units, a plurality of electric powersupply units whose location corresponds to a position where the electricpower reception apparatus is placed (for example, in step S51 shown inFIG. 5), receiving control information for controlling the supply of theelectric power, the control information being wirelessly transmittedfrom the electric power reception apparatus (for example, in step S89shown in FIG. 8), and controlling the supply of the electric poweraccording to the control information such that the electric power issupplied to the electric power reception apparatus from the selectedplurality of electric power supply units (for example, in step S111shown in FIG. 9).

According to an embodiment of the present invention, there is provided aprogram for use to execute an electric power supply process by acomputer in an electric power supply apparatus (for example, an electricpower supply apparatus 1 shown in FIG. 1) including a plurality ofelectric power supply units (for example, electric power supply units 11shown in FIG. 2) for supplying electric power by electromagneticinduction to at least one electric power reception apparatus (forexample, an electric power reception apparatus 2 shown in FIG. 1) placedon the electric power supply apparatus, the electric power supplyprocess including the steps of selecting, from a total plurality ofelectric power supply units, a plurality of electric power supply unitswhose location corresponds to a position where the electric powerreception apparatus is placed (for example, in step S51 shown in FIG.5), receiving control information for controlling the supply of theelectric power, the control information being wirelessly transmittedfrom the electric power reception apparatus (for example, in step S89shown in FIG. 8), and controlling the supply of the electric poweraccording to the control information such that the electric power issupplied to the electric power reception apparatus from the selectedplurality of electric power supply units (for example, in step S111shown in FIG. 9).

According to an embodiment of the present invention, there is providedan electric power reception apparatus (for example, an electric powerreception apparatus 2 shown in FIG. 1) adapted to receive electric powersupplied by an electric power supply apparatus (for example, an electricpower supply apparatus 1 shown in FIG. 1) including a plurality ofelectric power supply units (for example, electric power supply units 11shown in FIG. 2) adapted to supply electric power by electromagneticinduction, the electric power reception apparatus including at least oneelectric power reception means (for example, an electric power receptionunit 21 shown in FIG. 4) for receiving the electric power supplied byelectromagnetic induction from the plurality of electric power supplyunits, and a transmitting unit (for example, a communication unit 107shown in FIG. 4) for wirelessly transmitting control information forcontrolling the supply of the electric power to the electric powersupply apparatus when the electric power is supplied by electromagneticinduction from the electric power supply units.

According to an embodiment of the present invention, there is providedan electric power reception method for an electric power receptionapparatus (for example, an electric power reception apparatus 2 shown inFIG. 1) adapted to receive electric power supplied by an electric powersupply apparatus (for example, an electric power supply apparatus 1shown in FIG. 1) including a plurality of electric power supply units(for example, electric power supply units 11 shown in FIG. 2) adapted tosupply electric power by electromagnetic induction, the method includingthe steps of receiving electric power supplied by electromagneticinduction from the plurality of electric power supply units (forexample, in step S151 shown in FIG. 10), and wirelessly transmittingcontrol information for controlling the supply of the electric power tothe electric power supply apparatus when the electric power is suppliedby electromagnetic induction from the electric power supply units (forexample, in step S155 shown in FIG. 10).

Embodiments of the present invention are described below with referenceto the accompanying drawings.

FIG. 1 is a perspective view showing an example of a construction of anelectric power supply system according to an embodiment of the presentinvention.

This system includes an electric power supply apparatus 1 and anelectric power reception apparatus 2. On a surface of the electric powersupply apparatus 1, a placement surface 1 a is formed using a sheet ofmaterial which allows electromagnetic waves to pass through. When theelectric power reception apparatus 2 is placed on this placement surface1 a, the electric power supply apparatus 1 wirelessly supplies requiredelectric power to the electric power reception apparatus 2. That is, theelectric power supply apparatus 1 supplies electric power to theelectric power reception apparatus 2 without using an electric powersupply cable.

Examples of the electric power reception apparatus 2 are a notebook-typepersonal computer, a PDA, a portable telephone, and a PHS (PersonalHandyphone System) device, or a battery removable from such a device.

FIG. 2 is a diagram viewed from above and showing the electric powersupply apparatus 1 and the electric power reception apparatus 2 placedon the placement surface 1 a of the electric power supply apparatus 1,wherein for the purpose of illustration, parts hidden below upper partsare also shown. The electric power supply apparatus 1 includes nelectric power supply units 11-1 to 11-n adapted to supply electricpower to the electric power reception apparatus 2 by electromagneticinduction. The electric power supply units 11-1 to 11-n are arranged,for example, in a checkerboard pattern below the placement surface 1 a(behind the page of FIG. 2).

Hereinafter, when it is not necessary to distinguish individual electricpower supply units 11-1 to 11-n from each other, they will be referredto simply as electric power supply units 11.

The electric power reception apparatus 2 has an electric power receptionunit 21 disposed on the lower surface side (in contact with theplacement surface 1 a). The electric power reception unit 21 is adaptedto receive electric power supplied via electromagnetic induction causedby magnetic fields produced by the plurality of electric power supplyunits 11.

That is, as shown in FIG. 2, the electric power reception unit 21 (morespecifically, an electric power reception antenna 101 shown in FIG. 4)is formed so as to have a size (area) larger than the size (area) of oneelectric power supply unit 11. In the example shown in FIG. 2, theelectric power reception unit 21 of the electric power receptionapparatus 2 has a size containing four electric power supply units 11(an electric power supply unit 11-21, an electric power supply unit11-28, an electric power supply unit 11-29, and an electric power supplyunit 11-37).

FIG. 3 is a block diagram showing an example of a construction of theelectric power supply apparatus 1. The electric power supply apparatus 1includes n electric power supply units 11 (only one of them is shown inFIG. 3), a controller 41, a memory 42, a real time clock 43, and a powersupply circuit 44.

The electric power supply unit 11 includes a switch 51, an electricpower supply antenna 52, and a current detector 53.

The switch 51 turns on or off in accordance with a control signalsupplied from the selector 72 of the controller 41. When the switch 51is ON, an AC current is supplied to the electric power supply antenna 52from the power supply circuit 44. The current flowing through theelectric power supply antenna 52 generates a magnetic field. In otherwords, the electric power supply antenna 52 is a coil adapted togenerate a magnetic field by a current flowing through the coil.

One end of the current detector 53 is grounded. When the switch 51 is inthe on-state, the current detector 53 detects the magnitude of thecurrent flowing through the power supply antenna 52. The currentdetector 53 supplies a current detection signal corresponding to thedetected magnitude of the current to the selector 72 of the controller41.

The controller 41 includes an electric power supply controller 71, aselector 72, a communication unit 73 and a temperature sensor 74.

The electric power supply controller 71 includes a general-purpose CPU(Central Processing Unit) or a MPU (Micro Processing Unit). The powersupply controller 71 stores data into the memory 42 realized by a flashmemory or the like, as required. The power supply controller 71 controlsthe charging operation in accordance with data or a program stored inthe memory 42 or a clock pulse generated and supplied by the real timeclock 43.

Under the control of the power supply controller 71, the selector 72supplies a control signal for controlling the turning-on/off of theswitch 51 to electric power supply units 11. To the selector 72, acurrent detection signal indicating current value flowing throughelectric power supply antenna 52 is supplied from the current detector53. The selector 72 transfers the received current detection signal tothe electric power supply controller 71.

Under the control of the electric power supply controller 71, thecommunication unit 73 including an antenna and other parts communicateswith the electric power reception apparatus 2 using a radio wave or aninfrared ray.

The temperature sensor 74 measures the temperature of each of electricpower supply units 11-1 to 11-n or the temperature of a part of theplacement surface 1 a (for example, an area where electric power supplyunits 11-1 to 11-32, an area where electric power supply units 11-33 to11-64 are disposed, or an area where electric power supply units 11-65to 11-n are disposed) and transmits data indicating the measuredtemperature to the electric power supply controller 71. This allows theelectric power supply controller 71 to detect an occurrence of a circuitabnormality such as an electrical leak in electric power supply unit 11.If such an abnormality is detected, the electric power supply controller71 may turn off all the switches 51.

The power supply circuit 44 directly transfers the AC current suppliedvia the power cable to the electric power supply unit 11 or the powersupply circuit 44 generates an AC current with a predetermined frequencyfrom the AC current supplied via the power cable and supplies theresultant AC current to the electric power supply unit 11.

The electric power supply controller 71 is also connected to a driver 81as required. A removable storage medium 82 such as a magnetic disk, anoptical disk, a magnetooptical disk, or a semiconductor memory ismounted on the drive 81 as required, and a computer program is read fromthe removable storage medium 82 and installed into the memory 42, asrequired.

FIG. 4 is a block diagram showing an example of a construction of theelectric power reception apparatus 2. The electric power receptionapparatus 2 includes an electric power reception unit 21, a memory 121,a real time clock 122, and a battery 123. The electric power receptionunit 21 includes an electric power reception antenna 101, a rectifier102, an electric power reception controller 103, a terminal 104, aterminal 105, a switch 106, and a communication unit 107.

When an AC current flows through the electric power supply antenna 52 ofthe electric power supply unit 11, this AC current generates a magneticfield that induces an AC current through the electric power receptionantenna 101. That is, the electric power reception antenna 101 is a coilthrough which a current is generated by electromagnetic induction causedby a magnetic field generated by the electric power supply antenna 52.

The electric power reception antenna 101 is formed so as to be greaterin size than the electric power supply antenna 52.

The current induced in the electric power reception antenna 101 issupplied to the rectifier 102. The rectifier 102 rectifies the ACcurrent supplied from the electric power reception antenna 101 andgenerates a DC current. The rectifier 102 supplies the generated DCcurrent as operating power to the electric power reception controller103. The rectifier 102 supplies a current to the battery 123 via theterminal 104, the terminal 105, and the switch 106 to charge the battery123.

The electric power reception controller 103 includes a general-purposeCPU (Central Processing Unit) or a MPU (Micro Processing Unit). Theelectric power reception unit 21 and the battery 123 are, for example,an intelligent battery according to a smart battery standard.

When the current is supplied to the electric power reception controller103 from the rectifier 102, the electric power reception controller 103is activated. After the electric power reception controller 103 isactivated, the electric power reception controller 103 transmits andreceives information to and from the electric power supply apparatus 1via the communication unit 107. The electric power reception controller103 turns on the switch 106 and supplies electric power to the battery123 to charge it.

As required, the electric power reception controller 103 stores data inthe memory such as a flash memory 121 or acquires identificationinformation identifying the electric power reception apparatus 2 byreading it from the memory 121. The electric power reception controller103 also controls the charging operation in accordance with a programstored in the memory 121.

When the charging of the battery 123 is completed, more specifically,when the voltage between the terminal 104 and the terminal 105 reaches avalue indicating the completion of the charging of the battery 123, theelectric power reception controller 103 turns off the switch 106.

Therefore, if the charging of the battery 123 is completed, the chargingcurrent path including the rectifier 102, the terminal 104, the battery123, the terminal 105, and the switch 106 is cut off, and the chargingcurrent no longer flows.

Now, referring to a flow chart shown in FIG. 5, an explanation is givenon a process of selecting an electric power supply unit 11 at a locationcorresponding to the location of the electric power reception unit 21 ofthe electric power reception apparatus 2 placed on the placement surface1 a. This process is started when the electric power to the electricpower supply apparatus 1 is turned on or when the charging of theelectric power reception apparatus 2 is completed.

In step S41, the electric power supply controller 71 sets a variable Nto 1.

In step S42, under the control of the electric power supply controller71, the selector 72 forces a N-th electric power supply unit 11 togenerate a weak magnetic field. More specifically, the selector 72supplies an ON control signal to the N-th electric power supply unit 11.In response, the N-th electric power supply unit 11 supplies a currentto the electric power supply antenna 52 to generate a weak magneticfield.

Herein, the N-the electric power supply unit 11 is one of electric powersupply units 11-1 to 11-n shown in FIG. 2. For example, a first (N=1)electric power supply unit 11 refers to an electric power supply unit11-1, a second (N=1) electric power supply unit 11 refers to an electricpower supply unit 11-2, and a n-th (N=n) electric power supply unit 11refers to an electric power supply unit 11-n.

In step S43, the electric power supply controller 71 starts a timemeasurement which is performed by counting clock pulses supplied fromthe real time clock 43.

In step S44, the current detector 53 detects the value of a currentflowing through the electric power supply antenna 52 of the N-thelectric power supply unit 11.

In step S45, the electric power supply controller 71 determines whetherthe current value detected in step S44 is equal to or greater than athreshold value THa. More specifically, the electric power supplycontroller 71 determines whether the current value indicated by thecurrent detection signal supplied from the current detector 53 is equalto or greater than the threshold value THa.

The determination in step S45, as to whether the value of the currentflowing through the electric power supply antenna 52, is made for thefollowing reason.

FIG. 6 is a diagram showing the placement surface 1 a on which there isa foreign substance 201. In the example shown in FIG. 6, the foreignsubstance 201 is located at a position corresponding to the electricpower supply unit 11-21, the electric power supply unit 11-28, theelectric power supply unit 11-29 and the electric power supply unit11-37 of the electric power supply apparatus 1.

When the foreign substance 201 is metal and when the N-th electric powersupply unit 11 is, for example, the electric power supply unit 11-21, aneddy current is induced in the foreign substance 201 by the magneticfield generated by the electric power supply unit 11-21. When theforeign substance 201 is made of metal, the foreign substance 201 has alow resistance, and thus the eddy current causes the electric powersupply antenna 52 of the electric power supply unit 11-21 to have anovercurrent (an eddy current). Besides, the eddy current flowing in theforeign substance 201 causes the foreign substance 201 to be heated.

Thus, the determination in step S45 is made to prevent a current greaterthan an allowable value from flowing in the electric power supplyantenna 52 (see a later-described explanation of step S49).

In a case in which the determination in step S45 is that the currentvalue detected in step S44 is lower than the threshold value THa, thenin step S46 the electric power supply controller 71 determines whetherthe communication unit 73 has received electric power information andidentification information, which are transmitted from the electricpower reception apparatus 2 in step S151 described later with referenceto FIG. 10.

The current information indicates the voltage or the value of thecurrent that is caused to flow through the electric power receptionantenna 101 by the electromagnetic induction caused by the magneticfield generated by the N-th electric power supply antenna 52. Theidentification information identifies the electric power receptionapparatus 2.

In a case in which the determination in step S46 is that currentinformation and identification information are not received from theelectric power reception apparatus 2, then in step S47 the electricpower supply controller 71 the measurement of the time, which wasstarted in step S43 and which is performed by counting clock pulsessupplied from the real time clock 43, has reached a predetermined value(for example, 1 sec).

If it is determined in step S47 that the predetermined time has not yetelapsed, the process returns to step S46 and the above-described processis repeated from step S46.

On the other hand, in a case in which the determination in step S47 isthat the predetermined time has elapsed, the current information fromthe electric power reception apparatus 2 has not eventually received.That is, there is no electric power reception apparatus 2 on theelectric power supply apparatus 1, and thus in step S48 the electricpower supply controller 71 sets a flag to indicate that the electricpower reception unit 21 of the electric power reception apparatus 2 isnot located on the placement surface 1 a, at a position corresponding tothe N-the electric power supply unit 11. More specifically, for example,the electric power supply controller 71 sets the flag in the memory 42to “01” to indicate that the electric power reception unit 21 of theelectric power reception apparatus 2 is not present at the locationcorresponding to the N-th electric power supply unit 11.

After step S48 is completed, the process proceeds to step S52.

In a case in which the determination in step S45 is that the currentvalue is equal to or greater than the threshold value THa, it isconcluded that an overcurrent is flowing through the electric powersupply antenna 52 of the N-th electric power supply unit 11, and thus instep S49 the electric power supply controller 71 sets a flag to indicatethat there is a foreign substance 201 on the placement surface 1 a, at alocation corresponding to the location of the N-th electric power supplyunit 11. More specifically, for example, the electric power supplycontroller 71 sets the flag in the memory 42 to “10” to indicate thatthe foreign substance 201 is present on the placement surface 1 a, atthe location corresponding to the location of the N-th electric powersupply unit 11.

After step S49 is completed, the process proceeds to step S52.

If the determination in step S46 is that current information andidentification information have been received from the electric powerreception apparatus 2, then in step S50, the electric power supplycontroller 71 determines whether the current value indicated by thecurrent information is equal to or greater than a threshold value THb.

In a case in which the determination in step S50 is that the currentvalue indicated by the current information is equal to or greater than athreshold value THb, it is concluded that electric power is beingsupplied from an electric power supply unit 11 located within a range ofthe electric power reception unit 21 (the electric power receptionantenna 101) of the electric power reception apparatus 2, and thus instep S51 the electric power supply controller 71 sets the flag toindicate that the electric power reception unit 21 of the electric powerreception apparatus 2 is present on the placement surface 1 a, at alocation corresponding to the N-the electric power supply unit 11, andthe electric power supply controller 71 sets the identificationinformation so as to indicate the electric power reception unit 21 ofthe electric power reception apparatus 2. More specifically, forexample, the flag in the memory 42 is set to “11” to indicate that theelectric power reception unit 21 of the electric power receptionapparatus 2 is present on the placement surface 1 a, at a locationcorresponding to the N-the electric power supply unit 11, and theidentification information is set so as to indicate the electric powerreception unit 21 of the electric power reception apparatus 2.

In step S52, the electric power supply controller 71 stops thegeneration, which was started in step S42, of the weak magnetic field bythe N-th electric power supply unit 11. More specifically, the electricpower supply controller 71 supplies a control signal to the switch 51via the selector 72 to turn off the switch 51.

In step S53, the electric power supply controller 71 increments thevariable N by 1. For example, when the current value of the variable Nis “1”, the electric power supply controller 71 increments the variableN to “2”.

In step S54, the electric power supply controller 71 determines whetherthe current value of the variable N is equal to or smaller than thetotal number of electric power supply units 11, that is whether N≤thetotal number of electric power supply unit 11.

If the determination in step S54 is that the current value of thevariable N is equal to or smaller than the total number of electricpower supply units 11, that is, if N≤the total number of electric powersupply unit 11, then the process returns to step S42 to perform theabove-described process on a next electric power supply unit 11.

In a case in which the determination in step S54 is that the currentvalue of the variable N greater than the total number of electric powersupply units 11, that is, when N>the total number of electric powersupply unit 11, the process is ended.

In a case in which the determination in step S50 is that the value ofthe current indicated by the current information is smaller than thethreshold value THb, it is concluded that small power is being suppliedto the electric power reception unit 21 of the electric power receptionapparatus 2. Such a situation can occur, for example when a smallcurrent is induced in the electric power reception antenna 101 of theelectric power reception unit 21 by a magnetic field generated by theelectric power supply unit 11-38 whose location partially overlaps theelectric power reception unit 21 as shown in FIG. 2. In this case, theprocessing flow jumps to step S48 to perform the above-describedprocess.

The determination process in step S50 makes it possible for the electricpower reception unit 21 of the electric power reception apparatus 2 toreceive electric power only from those electric power supply units 11that are substantially completely located within the area of theelectric power reception unit 21 (the electric power reception antenna101). In the specific example shown in FIG. 2, the electric powerreception unit 21 of the electric power reception apparatus 2 receiveselectric power only from the electric power supply unit 11-21, theelectric power supply unit 11-28, the electric power supply unit 11-29and the electric power supply unit 11-37, whose locations are within thearea of the electric power reception unit 21 (the electric powerreception antenna 101). By controlling the supply of electric power suchthat electric power is supplied to the electric power reception unit 21only from electric power supply units 11 whose locations aresubstantially entirely within the area of the electric power receptionunit 21 (the electric power reception antenna 101), it becomes possibleto prevent a useless magnetic field from being generated, and thus itbecomes possible to supply electric power in a highly efficient manner.

For example, in the example shown in FIG. 2, the electric power supplyunits 11-21, 11-28, 11-29, and 11-37 are selected as electric powersupply units 11 for supplying electric power to the electric powerreception apparatus 2 whereby electric power is supplied efficiently asdescribed above.

FIG. 7 shows the electric power supply apparatus 1 in a state in which aplurality of electric power reception apparatus and/or foreignsubstances are present on the electric power supply apparatus 1. In theexample shown in FIG. 7, an electric power reception apparatus 2, anelectric power reception apparatus 220, and a foreign substance 231 arecurrently present on the electric power supply apparatus 1.

The electric power reception apparatus 220 and the electric powerreception unit 221 are respectively similar in structure to the electricpower reception apparatus 2 and the electric power reception unit 21,and thus duplicated explanations thereof are omitted herein. The foreignsubstance 231 is, for example, a metal plate.

In the example shown in FIG. 7, in the process of selecting electricpower supply units 11 described above with reference to the flow chartshown in FIG. 5, electric power supply units 11-21, 11-28, 11-29, and11-37 are selected as electric power supply units 11 for supplyingelectric power to the electric power reception apparatus 2, and electricpower supply units 11-40, 11-47, 11-48, and 11-56 are selected aselectric power supply units 11 for supplying electric power to theelectric power reception apparatus 220. However, for the foreignsubstance 231 in the form of the metal plate, no electric power supplyunits 11 are selected.

Next, referring to a flow chart shown in FIG. 8, a process ofauthenticating an electric power reception apparatus is described below.This process is started when in the process of selecting electric powersupply units 11 described above with reference to the flow chart shownin FIG. 5, electric power supply units 11 are selected and the flag inthe memory 42 is set so as to indicate that presence of an electricpower reception unit of an electric power reception apparatus isdetected.

When only one the electric power reception apparatus 2 is placed on theelectric power supply apparatus 1 as in the case of the example shown inFIG. 2, the electric power supply apparatus 1 performs theauthentication process described below to authenticate the electricpower reception apparatus 2.

On the other hand, when the electric power reception apparatus 2 and theelectric power reception apparatus 220 are placed on the electric powersupply apparatus 1 as in the case of the example shown in FIG. 7, theelectric power supply apparatus 1 may first perform the authenticationprocess described below for one of the electric power receptionapparatus 2 and the electric power reception apparatus 220 and then forthe other one, or the electric power supply apparatus 1 maysimultaneously perform the authentication process for the electric powerreception apparatus 2 and the electric power reception apparatus 220.

In the case in which the electric power supply apparatus 1 performs theauthentication process for a plurality of electric power receptionapparatus, each electric power reception apparatus transmitsidentification information identifying the electric power receptionapparatus to the electric power supply apparatus 1 when the electricpower reception apparatus transmits data to the electric power supplyapparatus 1 so that the electric power supply apparatus 1 can determinewhich data is received from which electric power reception apparatusbased on the identification information of electric power receptionapparatus stored, in step S51 shown in FIG. 5, in the memory 42.

In step S81, the electric power supply controller 71 transmits a requestsignal to an electric power reception apparatus via the communicationunit 73 to request the electric power reception apparatus to return anID (IDentification) as information based on which to authenticate theelectric power reception apparatus. Note that the electric powerreception apparatus, which should return the ID, is specified by anidentification number transmitted together with the request signal.

The ID of each electric power reception apparatus may or may not be thesame as the identification information of the electric power receptionapparatus. In the case in which the ID of the electric power receptionapparatus is the same as the identification information of the electricpower reception apparatus, steps S81 to S84 may be skipped. Note thatsteps S81 to S84 are necessary when information different from theidentification information of the electric power reception apparatus isused as the ID of the electric power reception apparatus.

In step S82, the electric power supply controller 71 starts a timemeasurement which is performed by counting clock pulses supplied fromthe real time clock 43.

In step S83, the electric power supply controller 71 determines whetherthe communication unit 73 has received the ID and identificationinformation of the electric power reception apparatus, which aretransmitted from the electric power reception apparatus in step S153described later with reference to FIG. 10.

If the determination in step S83 is that the ID and the identificationinformation of the electric power reception apparatus have not yet beenreceived, then in step S84 the electric power supply controller 71 thepredetermined time (for example, 1 sec) has elapsed since the timemeasurement was started in step S82.

If the determination in step S84 is that the predetermined time has notyet elapsed, the process returns to step S83 and the above-describedprocess is repeated from step S83.

On the other hand, if the determination in step S83 is that the ID andthe identification information of the electric power reception apparatushave been received, then in step S85 the electric power supplycontroller 71 determines whether the ID received from the electric powerreception apparatus is identical to the ID assigned to the electricpower supply apparatus 1. More specifically, the electric power supplycontroller 71 retrieves the ID from the memory 42 to determine whetherthe ID received from the electric power reception apparatus is identicalto one of registered IDs of apparatus (that are allowed to be charged).

If the determination in step S85 is that the ID received from theelectric power reception apparatus is identical to the ID assigned tothe electric power supply apparatus 1, then in step S86 the electricpower supply controller 71 transmits a request signal to the electricpower reception apparatus to transmit electric power informationassociated with the electric power reception apparatus. Also in thiscase, the electric power reception apparatus, which should transmitelectric power information, is specified by an identification numbertransmitted together with the request signal from the electric powersupply controller 71. Note that the electric power information refers toinformation based on which electric power is supplied by the electricpower supply controller 71. More specifically, the electric powerinformation indicates the maximum voltage allowed in the electric powerreception unit 21, the value of a current flowing into the electricpower reception unit 21, and the present value of the voltage betweenthe terminal 104 and the terminal 105.

In step S87, the electric power supply controller 71 starts a timemeasurement which is performed by counting clock pulses supplied fromthe real time clock 43.

In step S88, the electric power supply controller 71 determines whetherthe predetermined time (for example, 1 sec) has elapsed since the timemeasurement was started in step S87.

If the determination in step S88 is that the predetermined time has notyet elapsed, then in step S89 the electric power supply controller 71determines whether the communication unit 73 has received electric powerinformation and identification information, which are transmitted fromthe electric power reception apparatus in step S155 described later withreference to FIG. 10.

If the determination in step S89 is that electric power information andidentification information have not yet been received from the electricpower reception apparatus, the process returns to step S88 and theabove-described process is repeated from step S88.

On the other hand, if the determination in step S89 is that electricpower information and identification information have been received fromthe electric power reception apparatus, then in step S90 the electricpower supply controller 71 determines whether it is allowed to supplyelectric power requested by the received electric power information.More specifically, based on information stored in the memory 42, theelectric power supply controller 71 determines whether specificationsallow supplying of requested electric power to the electric powerreception apparatus.

If the determination in step S90 is that supplying of electric power tothe electric power reception apparatus according to the receivedelectric power information is allowed, then in step S91 the electricpower supply controller 71 sets the flag so as to indicate that theelectric power reception apparatus is a device that can be handled bythe electric power supply apparatus 1. More specifically, the electricpower supply controller 71 sets the flag in the memory 42 to, forexample, “001”, to indicate that the electric power reception apparatusis a device that can be handled by the electric power supply apparatus1.

If it is determined in step S84 that the predetermined time has elapsed(that can occur if the electric power reception apparatus is removedfrom the placement surface 1 a of the electric power supply apparatus1), or if it is determined in step S85 that the ID of the electric powerreception apparatus is not an ID registered in the electric power supplyapparatus 1, or if it is determined step S88 that the predetermined timehas elapsed (that can occur if the electric power reception apparatus isremoved from the placement surface 1 a of the electric power supplyapparatus 1), or if it is determined step S90 that supplying of electricpower to the electric power reception apparatus according to thereceived electric power information is not allowed, then in step S92 theelectric power supply controller 71 sets the flag so as to indicate thatthe electric power reception apparatus is not a device that can behandled by the electric power supply apparatus 1. More specifically, theelectric power supply controller 71 sets the flag in the memory 42 to,for example, “011”, to indicate that the electric power receptionapparatus is not a device that can be handled by the electric powersupply apparatus 1.

After step S91 or step S92 is completed, the process is ended.

By determining whether the ID and the electric power informationsupplied from the electric power reception apparatus are consistent withinformation stored in the electric power supply apparatus 1 in theabove-described manner, it is possible to increase the accuracy of theauthentication of the electric power reception apparatus 2.

Referring to a flow chart shown in FIG. 9, a process of supplyingelectric power to an electric power reception apparatus is describedbelow. This process is started when in the process of authenticating anelectric power reception apparatus described above with reference to theflow chart shown in FIG. 8, the flag is set in step S91 so as toindicate that the electric power reception apparatus is an apparatusthat is allowed to be handled by the electric power supply apparatus 1.

When only the electric power reception apparatus 2 is placed on theelectric power supply apparatus 1 as in the case of the example shown inFIG. 2, the electric power supply apparatus 1 performs a processdescribed below to supply electric power only to the electric powerreception apparatus 2.

On the other hand, when the electric power reception apparatus 2 and theelectric power reception apparatus 220 are placed on the electric powersupply apparatus 1 as in the case of the example shown in FIG. 7, theelectric power supply apparatus 1 may first perform the electric powersupply process described below for one of the electric power receptionapparatus 2 and the electric power reception apparatus 220 and then forthe other one, or the electric power supply apparatus 1 maysimultaneously perform the electric power supply process for theelectric power reception apparatus 2 and the electric power receptionapparatus 220.

In the case in which the electric power supply apparatus 1 performs theelectric power supply process for a plurality of electric powerreception apparatus, each electric power reception apparatus transmitsidentification information identifying the electric power receptionapparatus to the electric power supply apparatus 1 when the electricpower reception apparatus transmits data to the electric power supplyapparatus 1 so that the electric power supply apparatus 1 can determinewhich data is received from which electric power reception apparatus,based on the identification information of electric power receptionapparatus stored, in step S51 shown in FIG. 5, in the memory 42.

In step S111, based on the electric power information associated withthe electric power reception apparatus and received in step S89 in FIG.8, the electric power supply controller 71 controls the electric powersupply unit 11 to generate a magnetic field to supply electric power tothe electric power reception apparatus. More specifically, the electricpower supply controller 71 supplies, via the selector 72, an ON controlsignal to the switch 51 of the selected electric power supply unit 11corresponding to the identification information. In response, an ACcurrent is supplied to the electric power supply antenna 52 of theelectric power supply unit 11 from the power supply circuit 44, and amagnetic field is generated by a the current flowing through theelectric power supply antenna 52.

Note that in the magnetic field generation process in step S111, theelectric field is generated by all electric power supply units 11identified as corresponding to the electric power reception apparatus bythe identification information described in step S51 shown in FIG. 5.More specifically, in the specific case of the example shown in FIG. 2,the magnetic field is generated by the electric power supply unit 11-21,the electric power supply unit 11-28, the electric power supply unit11-29, and the electric power supply unit 11-37.

In step S112, the electric power supply controller 71 starts a timemeasurement which is performed by counting clock pulses supplied fromthe real time clock 43.

In step S113, the electric power supply controller 71 determines whetherthe communication unit 73 has received a signal indicating that chargingis being performed and identification information, which are transmittedfrom the electric power reception apparatus in step S160 described laterwith reference to FIG. 10.

If the determination in step S113 is that the signal indicating thatcharging is being performed and the identification information have notbeen received from the electric power reception apparatus, then in stepS114 the electric power supply controller 71 determines whether thecommunication unit 73 has received a signal indicating that charging iscompleted and identification information, which are transmitted from theelectric power reception apparatus in step S162 described later withreference to FIG. 10.

If the determination in step S114 is that the signal indicating thatcharging is completed and the identification information have not beenreceived from the electric power reception apparatus, then in step S115the electric power supply controller 71 determines whether thepredetermined time has elapsed since the time measurement was started instep S112. More specifically, for example, the electric power supplycontroller 71 determines whether 90 seconds have elapsed since the timemeasurement was started in step S112.

If the determination in step S115 is that the predetermined time has notyet elapsed, the process returns to step S113 to repeat the process fromstep S113.

If the determination in step S113 is that the signal indicating thatcharging is being performed and the identification information have beenreceived from the electric power reception apparatus, then in step S116the electric power supply controller 71 resets the count of time, whosecounting was started in step S112. That is, the electric power supplycontroller 71 resets the count of time to 0.

After step S116 is completed, the process returns to step S112, andsteps S112, S113, and S116 are performed repeatedly unit the signalindicating that charging is completed is received from the electricpower reception apparatus.

If it is determined in step S114 that the signal indicating thatcharging is completed and the identification information have beenreceived from the electric power reception apparatus, step S115 isskipped and the process proceeds to step S117. In step S117, theelectric power supply controller 71 stops the generation, which wasstarted in step S111, of the magnetic field by the electric power supplyunits 11 identified by the identification information as correspondingto the electric power reception apparatus.

More specifically, the electric power supply controller 71 supplies anOFF control signal to the switch 51 of the electric power supply units11 via the selector 72. As a result, the AC current supplied from thepower supply circuit 44 to the electric power supply antenna 52 of theelectric power supply units 11 is turned off, and the magnetic fieldgenerated in the electric power supply antenna 52 disappears.

Note that in step S114 described above, turning-off of the electricfield is performed for all electric power supply units 11 that startedgeneration of the electric field in step S111, that is, for all electricpower supply units 11 identified as corresponding to the electric powerreception apparatus by the same identification information described instep S51 shown in FIG. 5. More specifically, in the specific case of theexample shown in FIG. 2, turning-off of the magnetic field is performedin step S117 for the electric power supply unit 11-21, the electricpower supply unit 11-28, the electric power supply unit 11-29, and theelectric power supply unit 11-37.

If it is determined in step S115, the predetermined time (for example,90 sec) has elapsed since the time measurement was started in step S112,it is concluded that the electric power reception apparatus has beenremoved from the placement surface 1 a of the electric power supplyapparatus 1, and thus the processing in step S117 is performed in theabove-described manner. That is, because there is no electric powerreception apparatus to which to supply electric power, it is necessaryto perform the process in S117 to turn off the magnetic field generatedby the electric power supply units 11.

Referring to a flow chart shown in FIG. 10, a process performed by theelectric power reception apparatus to receive electric power isdescribed below. This process is started when the electric power supplyapparatus 1 generates a weak magnetic field in step S42 in FIG. 5whereby a current is electromagnetically included in the electric powerreception antenna 101 of the electric power reception unit 21 at alocation corresponding to electric power supply units 11, the current issupplied to the electric power reception controller 103 via therectifier 102, and thus the electric power reception controller 103 isactivated.

In step S151, the electric power reception controller 103 controls thecommunication unit 107 to transmit current information andidentification information stored in the memory 121 to the electricpower supply apparatus 1. In step S152, the electric power receptioncontroller 103 determines whether the communication unit 107 hasreceived a signal requesting the ID of the electric power receptionapparatus.

If the determination in step S152 is that the communication unit 107 hasnot received the signal requesting the ID of the electric powerreception apparatus, the process returns to step S151. However, if it isdetermined that the communication unit 107 has received the signalrequesting the ID of the electric power reception apparatus, then instep S153 the electric power reception controller 103 read the ID andthe identification information of the electric power reception apparatusfrom the memory 121 and transmits them to the electric power supplyapparatus 1.

In step S154, the electric power reception controller 103 determineswhether the communication unit 107 has received a signal requestingelectric power information. If the determination in the step S154 isthat the communication unit 107 has not received the signal requestingthe electric power information associated with the electric powerreception apparatus, then the process waits in step S154 until thesignal requesting the electric power information associated with theelectric power reception apparatus is received.

If it is determined in step S154 that the communication unit 107 hasreceived the signal requesting the electric power information associatedwith the electric power reception apparatus, then in step S155 theelectric power reception controller 103 controls the communication unit107 to transmit the electric power information and the identificationinformation.

In step S156, the electric power reception controller 103 startscharging of the battery 123. More specifically, the electric powerreception controller 103 turns on the switch 106 such that an AC currentis supplied from the electric power reception antenna 101 to therectifier 102, and a DC current produced by the rectifier 102 byrectifying the AC current is passed through a path including theterminal 104, the battery 123, the terminal 105, and the switch 106thereby charging the battery 123.

In step S157, the electric power reception controller 103 startscounting of clock pulses supplied from the real time clock 122 tomeasure the elapse of time. In step S158, the electric power receptioncontroller 103 determines whether a predetermined time (for example, 1min) has elapsed since the counting of time was started in step S157.

If the determination in step S158 is that the predetermined time (forexample, 1 min) has not yet elapsed, then in step S159 the electricpower reception controller 103 determines whether charging of thebattery 123 is completed. More specifically, the electric powerreception controller 103 determines whether the voltage between theterminal 104 and the terminal 105 has reached a value indicating thatthe charging of the battery 123 is completed.

If it is determined in step S159 that the charging is not completed, theprocess returns to step S158 to repeat the above-described process.

If it is determined in step S158 that the predetermined time (forexample, 1 min) has elapsed, then in step S160 the electric powerreception controller 103 controls the communication unit 107 totransmit, to the electric power supply apparatus 1, the identificationinformation and a signal indicating that the charging is beingperformed.

In step S161, the electric power reception controller 103 resets thecount value of the time whose counting was started in step S157. Thatis, the electric power reception controller 103 resets the count valueof the time to 0.

After step S161 is completed, the process returns to step S157.

If it is determined in step S159 that the charging of the battery 123 iscompleted, then in step S162, the electric power reception controller103 controls the communication unit 107 to transmit to the electricpower supply apparatus 1 identification information and a signalindicating that the charging is completed.

In step S163, the electric power reception controller 103 ends thecharging of the battery 123 by turning off the switch 106.

As described above, to one electric power reception unit 21, electricpower is supplied from a plurality of electric power supply units 11 atlocations corresponding to the location of the electric power receptionunit 21, and thus it is possible to quickly charge the electric powerreception unit 21.

Furthermore, it is possible to detect a foreign substance 201 such as ametal substance present on the electric power supply apparatus 1, and itis possible to prevent the foreign substance 201 from being heated andprevent a overcurrent from flowing through the electric power supplyantenna 52 of the electric power supply unit 11, thereby ensuring thatelectric power is supplied to the electric power reception apparatus ina highly safe manner.

Because electric power is wirelessly supplied to the electric powerreception apparatus 2 without using a connector, it is possible tosupply electric power to a plurality of electric power receptionapparatus, regardless of specifications thereof in terms of voltageand/or current.

If the electric power reception apparatus 2 transmits informationindicating the size of the electric power reception unit 21 (theelectric power reception antenna 101) to the electric power supplyapparatus 1, it becomes unnecessary, in the process of selectingelectric power supply units 11 shown in FIG. 5, to sequentially scan allelectric power supply unit 11 to detect electric power supply units 11at locations corresponding to the location of the electric powerreception unit 21.

More specifically, based on the size of the electric power receptionunit 21, a weak magnetic field is generated only by electric powersupply units 11 in a small area adjacent to a first-detected electricpower supply unit 11, and correct electric power supply units 11 aredetected simply by determining whether electric power supply units 11are at locations corresponding to the location of the electric powerreception unit 21. Thus it is possible to quickly detect electric powersupply units 11 at locations corresponding to the electric powerreception unit 21.

FIG. 11 is diagram showing another example of a construction of theelectric power reception unit of the electric power reception apparatus2. In this electric power reception apparatus 2, an electric powerreception unit 321-1 and an electric power reception unit 321-2 aresimilar in structure to the electric power reception unit 21. Both theelectric power reception unit 321-1 and the electric power receptionunit 321-2 are connected to the battery 123 of the electric powerreception unit 21 so that electric power is supplied to the battery 123from both the electric power reception unit 321-1 and the electric powerreception unit 321-2.

As shown in FIG. 11, each of the electric power reception unit 321-1 andthe electric power reception unit 321-2 is formed to have a size thatcan contain only one electric power supply unit 11.

The electric power reception apparatus 2 is placed on the placementsurface 1 a of the electric power supply apparatus 1 such that theelectric power reception unit 321-1 and the electric power receptionunit 321-2 are at locations respectively corresponding to the locationsof the electric power supply unit 11-21 and the electric power supplyunit 11-36 so that the electric power reception unit 321-1 and theelectric power reception unit 321-2 respectively receive electric powerfrom the electric power supply unit 11-21 and the electric power supplyunit 11-36.

In the following discussion, the electric power reception unit 321-1 andthe electric power reception unit 321-2 will be referred to simply aselectric power reception units 321 when it is not necessary todistinguish them from each other.

By constructing the electric power reception apparatus 2 so as to have aplurality of electric power reception units 321 as described above, itbecomes possible for the electric power reception apparatus 2 to receiveelectric power from a plurality of electric power supply units 11. Thus,as with the electric power reception apparatus 2 shown in FIG. 2, theelectric power reception apparatus 2 described above with reference toFIG. 11 is capable of completing the reception of electric power.

If the electric power reception apparatus 2 shown in FIG. 11 notifiesthe electric power supply apparatus 1 of the number of electric powerreception units 321 and the distance between electric power receptionunits 321, that is, the distance between the center of the electricpower reception unit 321-1 and the center of the electric powerreception unit 321-2, then, in the process of selecting electric powersupply units 11 (FIG. 5), it becomes unnecessary to detect electricpower supply units 11 at locations corresponding to the locations of theelectric power reception units 321 by sequentially scanning all electricpower supply units 11.

More specifically, for example, electric power supply units 11 atlocations that are likely to allow it to supply electric power to therespective electric power reception units 321 are detected on the basisof the locations of a first-detected electric power supply unit 11, thenumber of electric power reception units 321, and the distance betweenelectric power reception units 321. Thereafter, a weak magnetic field isgenerated by each detected electric power supply unit 11, and a judgmentis performed as to whether electric power supply units 11 are atlocations corresponding to the locations of the electric power receptionunits 321 whereby electric power supply units 11 to be used to supplyelectric power to the electric power reception units 231 are determined.This makes it possible to quickly determine electric power supply units11 at locations corresponding to the locations of the electric powerreception unit 321.

Because the electric power supply apparatus has the capability ofwirelessly supplying electric power without using a cable, it ispossible to easily supply electric power to electric power receptionapparatus regardless of specifications thereof in terms of voltageand/or current. As described above, the electric power supply apparatusis capable of easily and efficiently supplying electric power such thata plurality of electric power supply means supply electric power byelectromagnetic induction to the electric power reception apparatus, theselection means selects, from the total plurality of electric powersupply means, a plurality of electric power supply means whose locationcorresponds to the position where the electric power reception apparatusis placed, the receiving means receives the control information forcontrolling the supply of the electric power, the control informationbeing wirelessly transmitted from the electric power receptionapparatus, and the control means controls the supply of the electricpower according to the control information such that the electric poweris supplied to the electric power reception apparatus from the selectedplurality of electric power supply means. The electric power receptionapparatus receives electric power such that the electric power receptionmeans receives the electric power supplied by the electromagneticinduction from the selected plurality of electric power supply means,and the transmitting unit wirelessly transmits the control informationwhen the supply of electric power by the electromagnetic induction fromthe selected plurality of electric power supply means is received.

The sequence of processing steps described above may be performed bymeans of hardware or software. When the processing sequence is executedby software, a program forming the software may be installed from astorage medium onto a computer which is provided as dedicated hardwareor may be installed onto a general-purpose personal computer capable ofperforming various processes in accordance with various programsinstalled thereon.

A specific example of a storage medium usable for the above purposeinclude is a removable medium 82 (shown in FIG. 3) such as a magneticdisk (such as a floppy disk), an optical disk (such as a CD-ROM (CompactDisk-Read Only Memory) and a DVD (Digital Versatile Disk)), amagnetooptical disk (such as a MD (Mini-Disk, trademark)), and asemiconductor memory, in the form of a package medium in which a programis stored and which is supplied to a user separately from a computer. Aprogram may also be supplied to a user by preinstalling it on a memory42 or a hard disk disposed in the computer.

The program for executing the processes may be installed on thecomputer, as required, via an interface such as a router or a modem bydownloading via a wired or wireless communication medium such as a localarea network, the Internet, or digital satellite broadcasting.

In the present description, the steps described in the program stored inthe storage medium may be performed either in time sequence inaccordance with the order described in the program or in a parallel orseparate fashion.

In the present description, the term “system” is used to describe awhole of a plurality of apparatus organized such that they function as awhole.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. An electric power supply device, comprising: atleast one electric power supply section configured to supply electricpower to at least one electric power reception device wirelessly; aselection section configured to select the at least one electric powersupply section for the supply of the electric power to the at least oneelectric power reception device wirelessly, wherein a location of theselected at least one electric power supply section is entirely withinan area of the electric power reception device; a detection sectionconfigured to detect a foreign substance; and a control sectionconfigured to stop the electric power supplied to the at least oneelectric power reception device based on a presence of the foreignsubstance on a surface of the at least one electric power supplysection, wherein the foreign substance is in contact with the surface ofthe at least one electrical power supply section.
 2. The electric powersupply device according to claim 1, further comprising a communicationsection configured to transmit or receive control information to controlthe supply of the electric power to the at least one electric powerreception device, wherein the control section is further configured totransmit and receive information to or from the electric power receptiondevice via the communication section to authenticate the electric powerreception device.
 3. The electric power supply device according to claim1, further comprising a communication section configured to transmit orreceive control information to control the supply of the electric powerto the at least one electric power reception device, wherein based onreception of information by the communication section from the electricpower reception device, the selection section is further configured toselect the at least one electric power supply section as a firstelectric power supply section at the location, and wherein the at leastone electric power supply section is further configured to generate amagnetic field at a point of time at which the communication sectionreceived the information.
 4. The electric power supply device accordingto claim 3, wherein the control information is wirelessly transmittedfrom the electric power reception device such that the electric power issupplied to the electric power reception device from the selected atleast one electric power supply section.
 5. The electric power supplydevice according to claim 1, further comprising a communication sectionconfigured to transmit or receive control information to control thesupply of the electric power to the at least one electric powerreception device, wherein the detection section is further configured todetect an overcurrent that flows through the at least one electric powersupply section, wherein based on the detection of the overcurrent by thedetection section before reception of information by the communicationsection, the selection section is further configured to restrict theselection of the at least one electric power supply section throughwhich the detected overcurrent flows, and wherein the informationindicates the supply of the electric power to the at least one electricpower reception device.
 6. The electric power supply device according toclaim 1, wherein the at least one electric power supply section includesat least one coil.
 7. The electric power supply device according toclaim 6, wherein the at least one coil is further configured to generatea magnetic field.
 8. The electric power supply device according to claim1, further comprising a communication section configured to transmit orreceive control information to control the supply of the electric powerto the at least one electric power reception device.
 9. The electricpower supply device according to claim 1, wherein the control section isfurther configured to control the supply of the electric power based oncontrol information.
 10. An electric power reception device, comprising:at least one electric power reception section configured to receiveelectric power supplied by at least one electric power supply section ofan electric power supply device, wherein a location of the at least oneelectric power supply section is entirely within an area of the electricpower reception device; a detection section configured to detect aforeign substance; and a control section configured to transmitinformation to indicate the foreign substance to the electric powersupply device based on a presence of the foreign substance on a surfaceof the at least one electric power reception section, wherein theforeign substance is in contact with the surface of the at least oneelectric power reception section.
 11. The electric power receptiondevice according to claim 10, further comprising a communication sectionconfigured to transmit or receive the information to control the supplyof the electric power, wherein, the control section is furtherconfigured to transmit and receive the information to or from theelectric power supply device via the communication section toauthenticate the electric power reception device.
 12. The electric powerreception device according to claim 10, wherein the electric powersupply device includes at least one coil.
 13. The electric powerreception device according to claim 12, wherein the at least one coil isfurther configured to generate a magnetic field.
 14. The electric powerreception device according to claim 10, further comprising acommunication section configured to transmit or receive the informationto control the supply of the electric power.
 15. The electric powerreception device according to claim 10, wherein the control section isfurther configured to periodically transmit the information based ondetermination of the supply of the electric power from the electricpower supply device.